1. Field of the Invention
This invention relates in general to large diameter threaded connectors for the use in offshore drilling and production, and in particular to a means for locking the connectors together when made up.
2. Description of the Prior Art
In offshore drilling, large diameter pipes are used for various purposes. One type of connector joint for connecting the pipes together uses a threaded pin and box member. Often, the threads will be of a multistart type. That is, they will make-up in less than one full turn. This is useful because of wave and current action causing movement of the drilling vessel.
Because this type of connector makes up in less than one turn, there is a need to lock the connector against accidentally releasing. One type of locking device utilizes tabs formed in the rim of the box. These tabs are bent over into slots formed in the pin.
There are patents which show connector joints which have surfaces located above or below the threads and which engage each other in an interference fit. This interference fit would result in a greater requirement for break-out torque, thus making it less likely to unscrew. However, these surfaces also result in a greater requirement for make-up torque.